Potential applications of endogenous sulfide for enhanced denitrification of low C/N domestic wastewater in anodic mixotrophic denitrification microbial fuel cell: The mechanism of electrons transfer and microbial community

• Published in: The Science of the total environment Vol. 722; p. 137830
• Main Authors: Ai, Tao, Zhan, Hao, Zou, Linzhi, Fu, Junyu, Fu, Qibin, He, Qiang, Ai, Hainan
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.06.2020
• Subjects: Anodic denitrification; Electron transfer; Microbial interactions; Sulfate generation; Sulfate generation; Microbial interactions; Electron transfer; Anodic denitrification
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2020.137830

Anodic mixotrophic denitrification microbial fuel cell (MFC) was developed for pollutants removal and electricity generation in treatment of low C/N domestic wastewater. The experimental results show that the MFC achieved up to 100% of acetate, 100% of sulfide, and more than 91% of nitrate removal efficiency in all the MFCs. Particularly, thiosulfate was generated as the main intermediate of sulfide oxidation, and the sulfate generation ratio ranged from 66.93% to 73.76%. Those electrons produced during the acetate and sulfide oxidation were mainly used for denitrification and electricity generation. The microbial community analysis revealed that heterotrophic denitrifying bacteria (HDB) and sulfide-based autotrophic denitrifying bacteria (SADB) were the dominant bacteria for pollutants removal, and those facultative autotrophic bacterium (FAB) were key functional genera for high sulfate generation under both low and high sulfide concentrations. Meanwhile, the microbial functional prediction revealed that sulfide oxidation gene of Sqr and Sox were highly expressed. Moreover, a preliminary sulfide-based autotrophic denitrification (SAD) potential estimation indicated that the sulfide generated in the WWTPs had great potential for denitrification. [Display omitted] •An excellent removal of acetate, nitrate and sulfide was achieved in the anodic denitrification MFC.•The variations of acetate/sulfide altered the electrons transfer and microbial community structure.•The cooperation and competition among HDB, SADB and EB were elucidated.•Preliminary SAD potential estimation indicates that endogenous sulfide had great potential for denitrification.